In recent years, with the rapidly increasing supply of mobile terminals, it has become a modern person's necessity. Since the mobile terminal can provide not only a unique voice call service, but also all types of data transmission service, and various additional services, it may serve as a multimedia communication device. Recently, a mobile terminal with HAC for hearing handicapped persons has been developed.
The mobile terminal with HAC is managed according to an HAC standard. The HAC standard includes items such as intensity, Signal to Noise Ratio (SNR), and Frequency Response. When the mobile terminal satisfies given conditions requiring the foregoing items, the performance thereof can be recognized as a mobile terminal for HAC. In an embodiment, SNR among them is classified into a T-Category grade of T1 to T4 according to sound signal intensity and noise degree. When the mobile terminal has a grade T3 or T4, a performance thereof can be recognized as a mobile terminal for HAC.
To improve SNR, the related art increases a gain of a receiver dedicated amplifier in a modem chip of the mobile terminal. In general, because the receiver dedicated amplifier in the modem chip has a relatively small output, when a gain is extremely increased, signal intensity is increased but the quality of sound is distorted. When the quality of sound is distorted, a hearing handicapped person wearing a hearing aid cannot adequately hear a sound.